Electronic detection devices and computer managed control processes have been proposed for varying the speed of an automotive vehicle in response to sensed obstacles in or near the path of the vehicle. Proposed control systems have included an obstacle detection system with a transmitter to propagate a signal along the path of the vehicle and a receiver to collect reflections of the signal from an obstacle in or near the path. In addition, proposed systems included means to amplify and communicate such reflections to a microprocessor for resolving such information as the range between the vehicle and the obstacle and the time rate at which the range was changing (referred to as range rate). The range and range rate information is then applied in a defensive manner. The operator of the vehicle would be alerted of the potential hazard or a change would be effected in the operation of the vehicle independent of the operator.
The action required under such proposed procedures, whether to notify the operator or to change vehicle operation, is intrusive. False alarms, such as inaccurate indications that action is required to avoid an obstacle, can reduce vehicle operator satisfaction and can reduce confidence in the control system. Such false alarm conditions should therefore be minimized.
Many automatic vehicle control approaches are subject to frequent false alarm conditions. Such false alarm conditions may result from modeling error. For example, mathematical models determining conditions under which alarm conditions are activated may be oversimplified, relying on broad assumptions about vehicle behavior and operator requirements. Use of such proposed models has resulted in limited commercial acceptance of automatic vehicle controls.
It would, therefore, be desirable to provide an improved process for using range and range rate data from an obstacle detector to determine alarm conditions that are more compatible with the actual reaction of the operator and, therefore, more useful in increasing safe operating conditions.